1. Lab Project #3: BufLab — Buffer Overflow Attacks
Hugh C. Lauer
Department of Computer Science
(Slides shamelessly adapted from Bryant & O’Hallaron)
CS-2011, D-term 2013
Lab Project #3: BufLab

2. Objective and Approach
To gain a deeper understanding of IA-32 calling conventions and stack structure …
… by devising a series of buffer overflow attacks on an executable file called bufbomb
I.e., make a “cookie” show up in places in memory where it ordinarily would not show up
Warning! What you are about to do would be highly illegal if carried out against someone else’s system outside of this class project!
CS-2011, D-term 2013
Lab Project #3: BufLab

3. Obtaining Buflab See handout on course website
Check out a buffer bomb from
You will get a tar.gz file containing three programs:–
bufbomb — the bomb itself, customized for you
makecookie — generates a “cookie” based on your ID
hex2raw — converts a series of hexadecimal byte codes to a raw string containing an attack
CS-2011, D-term 2013
Lab Project #3: BufLab

4. This Project Five levels of buffer attack For each one, you must:–
Write some C code based on your disassembly of the bufbomb binary
Generate the corresponding IA-32 assembly code (gcc –s) and create an exploit string
Convert this into a raw string to pass into stdin ( i.e., hex2raw)
Successfully plant your cookie in bufbomb
When successful, submit the exploit string to the online grading server
(using the –s switch)
CS-2011, D-term 2013
Lab Project #3: BufLab

5. Working on Buflab This is supposed to work on any Linux system
But bufbomb won’t link with CCC libraries!
Must be submitted from CCC systems
Will disable host name checking
No penalty for mistakes
Due date:–April 17, 2013, 11:59 PM
CS-2011, D-term 2013
Lab Project #3: BufLab

6. Questions?
CS-2011, D-term 2013
Lab Project #3: BufLab